Brief History

Kagomori castle (河後森城) is located over a round shaped hill of about 50 meter height from hillside, at the side of Hiromi-gawa river in the center of Matsuno town, a mountainous town in the south part of current Ehime prefecture. Hiromi-gawa river is a major tributary of Shimanto-gawa river which is known as a clear river flows around south part of Shikoku island.The main stream of Shimanto-gawa river flows like Omega letter between Kochi plain and Nakamura plain which are two major plain of current Kochi prefecture. Hiromi-gawa river starts only 10 kilometer away from western coast of Shikoku island, passes Shikoku mountains and merges to Shimanto-gawa river at the top of its Omega shape. Because of its geographical condition, Hiromi-gawa river called as Matsumaru Kaido road was used as a communication route between former Iyo province (Ehime prefecture )and Tosa province (Kochi prefecture).

Origin of Kagomori castle

There has been several routes which connect Dogo plain, the center of Iyo province, and Kochi plain, the one of Tosa province, including Matsuyama Kaido road which becomes current Route 33 or Tosa-Kita Kaido road runs along current Kochi Jidoshado Expressway. Compared with such mountainous road, Hiromi-gawa river route was longer distance but gentle road, which is used as a railway route of Yodo-sen line. Matsuno area places at the Iyo province side of valley road of Hiromi-gawa river, thus it was an important point to control the communication of the border.Precise year is unknown but Kagomori castle might be built in 14th or 15th century by Watanabe clan. Watanabe clan was a strong local lord and regarded as the first position of 15 major retainers of Saionji clan which dominated southwestern edge of Iyo province including current Ozu area or Uwajima area. At the same time, Tosa Nakamura area at the opposite side of the border was governed by Ichijo clan at Nakamura castle.As both of Saionji clan and Ichijo clan were descendants of high class noble of Kyoto city, at first both clan keep friendship. Under such circumstance, Noritada Watanabe (?-?), who was a relative of Ichijo clan was adopted by Watanabe clan and became the lord of Kagomori castle.

Battle between parental home and master

However, in the middle of 16th century, Ichijo clan allied with Otomo clan which was the lord of Bungo province (Oita prefecture) and aimed at expansion for neighbor areas. In 1568 Ichijo clan raised their army and intruded into Iyo province, under alliance with Utsunomiya clan which was the lord of Uwajima area. To cope with this attack, Saionji clan asked assistance to Mouri clan , a strong warlord of Chugoku region and rival of Otomo clan, along with Kono clan at Matsuyama area. After one year campaign, Mouri army broke Ichijo army and pushed out them from Iyo province. But at during this battle, Noritada Watanabe became caught between Saionji clan and Ichijo clan just looked at this battle and did not cooperate with Saionji clan. After the retreat of Ichijo army, Saionji clan attacked Watanabe clan at Kagomori castle, and Noritada Watanabe surrendered to Saionji clan submitting hostage.On the other hand, Ichijo clan significantly lost its power and authority from this defeat, was overrode by Motochika Chosokabe (1539-1599), a talented warlord rose from small local lord. In 1574 Motochika expelled Kanesada Ichijo (1543-1585) who was the leader of Ichijo clan from Tosa province, and totally broke Kanesada who returned next year at the battle of Shimanto-gawa river.

Struggle against strong enemy

Motochika who captured the territory of Ichijo clan targeted the unification of Shikoku island, and next aimed at Iyo province from 1577. Facing incomparably strong enemy Saionji clan was forced to the corner, but well fought over five years. During this battle Noritada Watanabe stubbornly protected Kagomori castle, but was finally lost the castle because of the betrayal of his retainer around 1580. In 1584 Saionji clan finally surrendered to Chosokabe clan. However,, in the next year facing the Shikoku campaign of central ruler Hideyoshi Toyotomi (1537-1598), Motochika Chosokabe also surrendered to Toyotomi clan and lost Iyo province. Kagomori castle was confiscated and became the territory of Takakage Kobayakawa (1533-1597) who gained Iyo province.After the move of Takakage to Kyushu island in 1587, Kagomori castle was given to Katsutaka Toda (?-1594) who completely ruined Saionji clan. But as Katsutaka died in ill with no successor, Kagomori castle became the territory of Takatora Todo (1556-1630). Takatora was an excellent castle builder who totally renovated Ozu castle and Uwajima castle into modern castle, and also reformed Kagomori castle as a border castle against Chosokabe clan which remained as the lord of Tosa province.

Structure of Kagomori castle

The main part of Kagomori castle spreads over J shaped hill longs over 500 meter, with a gap toward southeast. Central area of the castle is a rectangular area of 30 meter long and 10 meter wide, at the root of the curve. The western line of the area was protected by stone wall, which was broken but the root of the wall slightly remains. It is said that there was a main tower at this area, and later moved to Uwajima castle (Ehime prefecture) as Tsukimi turret.At the both of east and south from central area, over 10 areas spread along the ridge, being separated by clay walls and dry moats with ends securely protected by horizontal moats. These areas might keep original shape of the castle, but reformed into flat space and steep clay wall. The large dry moat separates main castle and old castle at the east of central area was used as a main gate toward castle town. Surrounding core area, outer forts were built around the castle. The valley surrounded by the curve of J letter was used as a residence of the lord and water source. The curved line of areas aside of the river seems like a coiling water dragon protecting a treasure at inside. Total size of the castle is about 500 meter square, and its size and perfection is prominent compared with neighbor castles maintained by Saionji clan or Chosokabe clan.

Afterward of castle

In 1608, Takatora Todo moved to the lord of Tsu castle (Mie prefecture), and Nobutaka Tomita (?-1633) who was the lord of Tsu castle became the lord of Uwajima domain including Kagomori castle in return. But Tomita clan lost its territory in 1613, and next year Hidemune Date (1591-1658), the eldest son of Masamune Date (1567-1638), famous warlord of Sendai castle (Miyagi prefecture) but could not succeed his father, was appointed as the lord of Uwajima domain.Under Date clan, its highest retainer Kageyori Kori (1559-1625) was appointed as the lord of Kagomori castle. This shows the importance of Kagomori castle as a forefront far away from its main base Uwajima castle. However, because of Ikkoku Ichijo Rei (one domain one castle rule) published in 1615, Kagomori castle was abolished and ended its history.Now all building was lost but shapes of the castle well remain around the hill. Castle site is prepared to show the structure of the castle, based on the result of investigation and excavation. Curved blue line of Hiromi-gawa river seen from castle site used as a route for trade in peacetime and invasion in wartime exactly show the reason of development of the castle unmatched to quiet town. For local residents the shape of the castle might be seen as a water dragon which protected the clear stream.